I tried different ones out after some problems in games, but ended up able to replicate them with my retail carts, in the end. The GBA and DS Castlevanias are the worst, if for no other reason than needing to play straight through for hours to replicate a given problem (infiite slashing animation, lockups in certain rooms, corrupted saves).

Low class rated Sandisk, Kingston, Transcend, A-Data, and Patriot, are, IMO, hard to fault, when random performance is needed. I haven't tried any others than above list in my flashcart, but phone applications can be sensitive to random reads, too, making so many class 10 cards worthless. Samsung and Toshiba are great, with good sequential and random performance, but they are proud of it. If the price difference weren't less than 20% at the time, I would have bought a Patriot or Transcend 32GB, arther than Samsung.

I've never, ever, ever had a good experience, long-term, with any flash product branded PNY or Lexar, nor has anyone I've known who's bought their USB, CF, or SD cards, and I have had multiple bad RMA experiences with PC AIBs from PNY. Everyone I know, it seems, that uses flash often, has independently been burned by PNY, Lexar, or both, and so learned to avoid them.

Whichever is the cheapest and is at least class 6 or class 10 if it's only like a dollar or two more. Most brands are quire reliable and I back up my data often anyways. Only times I would be cautious is with some unheard of brand from some ebay seller or other similar situations.

I have some unlabeled SD card because it was cheap and I wanted a 4GB card. I also don't know the class of it because it just says SD on it.

Click to expand...

That card simply has no class. There isn't a requirement that they be off some class, just that if a card is rated, it must give sequential write performance of that many (2,4,6,10) MB per second. How often does your flash cart, phone, tablet, or Raspeberry Pi need fast sequential write speeds? Not often. But, there is no offical spec for 16K or 32K random reads.

I have some unlabeled SD card because it was cheap and I wanted a 4GB card. I also don't know the class of it because it just says SD on it.

Click to expand...

That card simply has no class. There isn't a requirement that they be off some class, just that if a card is rated, it must give sequential write performance of that many (2,4,6,10) MB per second. How often does your flash cart, phone, tablet, or Raspeberry Pi need fast sequential write speeds? Not often. But, there is no offical spec for 16K or 32K random reads.